1. Field of the Invention
This invention relates to a process for making free-flowing, compressible powders, and to tableting of an active ingredient therein from such powders, and more particularly, to a co-processing method for forming powders and tablets having advantageous physical and use properties.
2. Description of the Prior Art
Direct compression is a process by which a powder blend of an active ingredient, such as a drug, and a suitable excipient or filler, which is capable of flowing uniformly into a die cavity, are compressed directly into an acceptable tablet. Direct compression excipients or fillers include microcrystalline cellulose, anhydrous lactose, spray dried lactose and dicalcium phosphate.
The advantages of direct compression include avoiding exposure of the active material to moisture and heat, and long-term physical and chemical stability due to the substantial absence of moisture or direct exposure of the drug particles.
The disadvantages of direct compression include the requirement of flowability of the powder blends, especially in high speed tabletting, limited particle bonding and dilution capacities of the filler/binder.
Flowability of the powder blends can be partially overcome by admixture with lubricants; however, this may hinder the hardness of the tablet and dissolution of the drug. Particle bonding and dilution can be overcome by including one or more filler/binders in the tablet. Blending problems also may be overcome by using a filler with a range of particle sizes and/or densities corresponding to the active material.
Co-processing which is defined as the use of a combination of two or more filler/binder materials, for direct compression of tablets, can improve upon the currently available individual excipients without changing their chemical structure.
Starch (Cornstarch USP) is a widely accepted material for pharmaceutical use. Starch is a well known disintegrant in solid dosage form, and its aqueous solutions are advantageous as a binder in wet granulation tableting processes. However, cornstarch alone does not possess two properties necessary for making good compacts, namely compressibility and fluidity. Cornstarch does not form hard compacts under moderate compression forces, and, also, it exhibits only minimal dilution potential. Starch 1500 is the commercially available form of modified starch.
Accordingly, it is an object of this invention to provide an improved co-processing process for making free-flowing, compressible powders, which in combination with an active medicinal material, may be directly compressed to form a tablet having commercially-acceptable fluidity, compressibility, dissolution times, lubricity, and dilution potential.